This read-only CoriantTypesYesNo value indicates whether a specific replacement signal is sent out during the hold-off period on this OTU4 (about 111.8 Gbit/s) line-side OTN facility, defaulting to no. Sending such a signal during the hold-off window avoids the downstream equipment taking its own consequent action (like an unnecessary protection switch) before the local hold-off timer has even expired. For example, enabling this on the OTU4 facility on slot 3 means that during a brief hold-off window after a fault, downstream gear sees a defined signal rather than raw noise that might otherwise trigger its own premature response.